Add supported python version to README (#226)

Signed-off-by: Won Jun Jang <wjang@uber.com>

CONTRIBUTING.md

@@ -11,8 +11,6 @@ We gratefully welcome improvements to documentation as well as to code.
 
 ## Developing
 
-Jaeger Python client currently only supports Python 2.7.
-
 This repository uses [virtualenv](https://pypi.python.org/pypi/virtualenv) and `pip` to manage dependencies.
 To install all dependencies, run:
 

README.md

@@ -1,4 +1,4 @@
-[![Build Status][ci-img]][ci] [![Coverage Status][cov-img]][cov] [![PyPI version][pypi-img]][pypi] [![FOSSA Status][fossa-img]][fossa]
+[![Build Status][ci-img]][ci] [![Coverage Status][cov-img]][cov] [![PyPI Version][pypi-img]][pypi] [![Python Version][pythonversion-img]][pythonversion] [![FOSSA Status][fossa-img]][fossa]
 
 # Jaeger Bindings for Python OpenTracing API
 
@@ -166,5 +166,7 @@ Please make sure your framework does the same.
 [cov]: https://codecov.io/gh/jaegertracing/jaeger-client-python
 [pypi-img]: https://badge.fury.io/py/jaeger-client.svg
 [pypi]: https://badge.fury.io/py/jaeger-client
+[pythonversion-img]: https://img.shields.io/pypi/pyversions/jaeger-client.svg
+[pytonversion]: https://pypi.org/project/jaeger-client
 [fossa-img]: https://app.fossa.io/api/projects/git%2Bgithub.51.al%2Fjaegertracing%2Fjaeger-client-python.svg?type=shield
 [fossa]: https://app.fossa.io/projects/git%2Bgithub.51.al%2Fjaegertracing%2Fjaeger-client-python?ref=badge_shield

setup.py

@@ -33,6 +33,7 @@
         'License :: OSI Approved :: Apache Software License',
         'Natural Language :: English',
         'Programming Language :: Python :: 2.7',
+        'Programming Language :: Python :: 3.5',
         'Programming Language :: Python :: 3.6',
     ],
     install_requires=[